Technical Field
The present invention relates to a patch preparation containing an acid addition salt of a basic medicament as active ingredient, more specifically, a patch preparation in which a scavenger of acid attached to the medicament is contained to encourage production of free base.
Description of the Related Art
An example of a known technique for accelerating the transdermal absorption of a medicament is dissolving the medicament in a fatty acid-based ionic liquid (Patent Document 1).
On the other hand, basic medicament is often distributed in its acid addition salt such as hydrochloride salt. However, acid addition salt like that has tendency exhibit lower transdermal permeability relative to its free base. Therefore, it has been proposed to eliminate acid addition salt in drug formulation by adding neutralizing agent such as sodium hydroxide (Patent Document 2). In the document, problems of agglomeration or growth of metal salt with time which are produced by the neutralize reaction are solved with use of absorbent. However, a satisfying result for transdermal permeability had not given.